I'm trying to use the Heroku Rails scheduler.
https://devcenter.heroku.com/articles/scheduler
I don't know where to write my function that is supposed to be accomplished. Where do I write this?
In their case the function is called NewsFeed.update
i didn't used that heroku scheduler but i can give you some idea. it is very simple. You just have to write some worker or rake task. We will use rake task. For that you have create file lib/tasks/news_feeds_update.rake
and put this
namespace :news_feed do
task :update => :environment do
# body of method
# not sure what you wanted, so i put the below method.
NewsFeed.update
end
end
Now, you can add this task/method into heroku scheduler . Also you can call this task or method by doing this in command line
rake news_feed:update
Related
I have a rake task that works with models. But I need to tell the models that they are being used from Rake instead of within the app. My best idea is to set an environment variable on the command line before running the rake task, but that requires everyone on the team to remember to use the environment variable. Specifically, I have an if statement to skip loading Delayed::Job's handle_asynchronously while running the rake task.
class Thing < ActiveRecord::Base
searchable do
string :title
text :title, :content
end
handle_asynchronously unless ENV['MIGRATINGDATA']
end
When we run our migration task we do this:
MIGRATINGDATA=true bundle exec rake project:migrate_data
I'd like to get rid of the need for the special addition to the command line. Our migration code loads a fake Sunspot instance to turn off indexing while migrating the data.
Just set something at the top of your Rakefile:
ENV['HELLO_RAKE'] = true
require_relative 'config/application'
Rails.application.load_tasks
Instead of using ENV you could, if you wanted, set a constant, e.g. HELLO_RAKE = true and then check defined?(HELLO_RAKE).
An alternative is to just check if the running program is rake:
handle_asynchronously unless File.basename($0) == "rake"
A downside to both of these approaches is that they will be in effect any time you're using Rake, which will include other Rake tasks not related to migrations.
If your models care if you are using them from a rake task or not, you are doing something wrong. Instead you can add parameters to certain methods for example. In your specific use case, you can run jobs immediately instead. Put this at the start of your rake task:
Delayed::Worker.delay_jobs = false
I have some problems with one of gem supporting ActiveModel caching. When I'm using observer for cached model, during application initialization it tries to describe table to get all fields names.
The same thing is done when rake task is running, including db:migration. In that case there is some circular reference error. I'd like to detect current rake task, to skip gem initialization, but I don't know how to find out was code invoked through rake task. How to check it?
I dont get exactly what you are trying to do, but here is an example of getting the task name.
task :testing do |task_name|
puts task_name
end
This question has been asked a few places, and I didn't think any of the answers were very good... I think the answer is to check Rake.application.top_level_tasks, which is a list of tasks that will be run. Rake doesn't necessarily run just one task.
If you run your task via rake task or bundle exec rake task you can check it in your initializer simply by:
if $0.end_with?('rake')
# rake stuff
else
# non-rake stuff
end
You can use $PROGRAM_NAME instead of $0 if you like.
This is a 2nd part to the following question:
Where to put model "utility" functions in Ruby on Rails
Problem is, I need access to these utility functions from a rake task as well. Using the accepted technique in in the other thread, I get an "undefined method" error when accessing my model from a rake task.
What is the best way to fix this?
Thanks
You probably need to define your rake task as dependent on the Rails environment:
task :my_task => :environment do
# Will load Rails stack before executing this block
MyModel.foo
end
The default behavior is to load almost nothing, so you won't have access to your models unless you ask for it.
I have a model, let's call it Foobar. I want to be able to run a cron job to update an attribute of all objects that are instances of Foobar. So, in pseudocode, it might be something like this:
Foobar.all.each do |foobar|
foobar.update_attributes({:my_attribute => 'updated'});
end
Now, let's say I wrap that in a class method called Foobar.run_update().
Calling Foobar.run_update() would work fine from the controller, or even from a view. But, what I want to do is run run_update() from the Rakefile so that I can tie it into a cron run. But, the Foobar class is not available to Rake when it is called from crontab.
How can I resolve that? How can I access the class methods of Foobars from Rake, when Rake is called from cron?
Thank you very much for your help.
By rake, if you mean a rake task then adding => :environment loads the rails environment for the task and you be able to call the Foobar.run_update method there. Like,
namespace :foobar do
task :update => :environment do
Foobar.run_update
end
end
And you should just be able to call rake foobar:update from the console and have it scheduled as a cronjob.
You can load up the Rails environment by requiring config/environment.rb:
ENV["RAILS_ENV"] ||= "production"
require '/where/your/rails/project/is/config/environment.rb'
In my Sinatra apps I typically have the file models/init.rb which requires Sequel, sets up my DB connection, and then uses require_relative to require all my model files. My main application then does require_relative "models/init".
With this setup any other script (including IRB) all I have to do is require the models/init.rb file myself, and I have full access to the same models and DB connection that the application has.
I have a Rails app with some basic models. The website displays data retrieved from other sources. So I need to write a Ruby script that creates new instances in my database. I know I can do that with the test hooks, but I'm not sure that makes sense here.
I'm not sure what this task should look like, how I can invoke it, or where it should go in my source tree (lib\tasks?).
For example, here's my first try:
require 'active_record'
require '../app/models/mymodel.rb'
test = MyModel.new
test.name = 'test'
test.save
This fails because it can't get a connection to the database. This makes sense in a vague way to my newbie brain, since presumably Rails is doing all the magic work behind the scenes to set all that stuff up. So how do I set up my little script?
You can load the entire rails environment in any ruby script by simply requiring environment.rb:
require "#{ENV['RAILS_ROOT']}/config/environment"
This assumes the RAILS_ROOT environment variable is set, see my comment for other ways of doing this.
This has the added bonus of giving you all the nice classes and objects that you have in the rest of your rails code.
To kick off your processes it sounds like cron will do what you want, and I would also add a task to your capistrano recipe that would add your script to the crontab to periodically get the data from the external source and update your DB. This can easily be done with the cronedit gem.
The cron approach does have some drawbacks, mostly overhead and control, for other more sophisticated options see HowToRunBackgroundJobsInRails from the rails wiki.
I agree with the answer above but you have to include => :environment in your task or it will not load the Rails environment.
e.g.,
namespace :send do
namespace :trial do
namespace :expiry do
desc "Sends out emails to people who's accounts are about to expire"
task :warnings => :environment do
User.trial_about_to_expire.has_not_been_notified_of_trial_expiry.each do |user|
UserMailer.deliver_trial_expiring_warning(user)
user.notified_of_trial_expiry = true
user.save
end
end
end
end
end
I'd suggest creating custom rake tasks (lib/task/foo.rake). This give you easy access to most of the functionality of your rails app.
namespace :foo do
desc 'do something cool'
def something_cool
test = MyModel.new
test.name = 'test'
test.save
end
end
Then:
$ rake -T foo
rake foo:something_cool # do something cool
You can even run the tasks via a cronjob.
I wrote up a post about this a while back.
http://www.rawblock.com/2007/06/14/ruby-oracle-mac-os-x-pain-jruby-and-activerecord-jdbc-to-the-rescue/
You can open a connection in your scripts as such:
ActiveRecord::Base.establish_connection(
:adapter => "mysql",
:username => "root",
:host => "localhost",
:password => "******",
:database => "******"
)
I'm sure there is a more elegant way to do it, so that it grabs the info from your database.yml.
There are few steps to this and more details needed to really answer well.
You say your site retrieves data from other sources? How often? If it is semi-regularly you definitely want to look into background processing/messaging. If it is frequently you really want to avoid loading your rails environment every time your script runs since you will be paying too high a startup tax each time.
There are a multitude of options out there you will want to research. Reading about each of them, particularly reviews from people who post about why they made the choice they did, will give you a good feel for what questions you need to ask yourself before you make your choice. How big a job is loading the data? etc...
Off the top of my head these are some of the things you may want to look into
Script/Runner & Cron
Background/RB
Starling
Workling
MemcacheQ
Beanstalk
Background Job (Bj)
delayed_job (Dj)
Daemon Generator
Check out my answer in "A cron job for rails: best practices?".
It contains two examples for using cron to run Rake tasks and class methods (via script/runner). In both cases, Rails is loaded and you can use your models.
Nice Joyent write up of using rake to run rails tasks from a cron job - http://wiki.joyent.com/accelerators:kb:rails:cron
Easiest way to run ruby tasks that interact with rails app/models is to make Rails generate Rake tasks for you!! :)
Here's an example
run rails g task my_namespace my_task
This will generate a file called lib/tasks/my_namespace.rake which looks like:
namespace :my_namespace do
desc "TODO: Describe your task here"
task :my_task1 => :environment do
#write any ruby code here and also work with your models
puts User.find(1).name
end
end
Run this task with rake my_namespace:my_task
Watch your ruby code task that interacts with rails modal run!